v3.25.3

Earnings and Dividends per Common Share - Summary of Computation of Basic and Diluted Earnings per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Earnings Per Share [Abstract]
Net income attributable to Koppers	$ 23.8	$ 22.8	$ 26.3	$ 62.6
Weighted average common shares outstanding (in thousands):
Basic (in shares)	19,654	20,409	19,964	20,790
Effect of dilutive securities (in shares)	558	552	450	658
Diluted (in shares)	20,212	20,961	20,414	21,448
Earnings per common share:
Basic (in dollars per share)	$ 1.21	$ 1.12	$ 1.32	$ 3.01
Diluted (in dollars per share)	$ 1.17	$ 1.09	$ 1.29	$ 2.92
Antidilutive securities excluded from computation of diluted earnings per common share (in shares)	291,000	274,000	582,000	61,000

Earnings per common share continuing operations.

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Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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Koppers Holdings Inc. 10-Q